This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Failure to eradicate infiltrating glioma cells using conventional treatment regimens results in tumor recurrence and is responsible for the dismal prognosis of patients with glioblastoma multiforme (GBM). This is due to the fact that these migratory cells are protected by the blood-brain barrier (BBB) and the blood brain tumor barrier (BBTB) which prevents the delivery of most anti-cancer agents. We have evaluated the ability of monocytes/macrophages (Mo/Ma) to cross the BBB in rats. This will permit access of anti-cancer agents such as nanoparticles to effectively target the infiltrating tumor cells, and potentially improve the treatment effectiveness for malignant gliomas.